1. Field of the Invention
The present invention relates to absorbing substances for the removal of catalyst poisoning gases, viz. the compounds of hydrogen with the elements of Group V of the Periodic Table of Elements, particularly with arsenic (As) and antimony (Sb), from the oxyhydrogen mixtures which are generated during the operation of lead-acid storage batteries. The invention further relates to methods of producing such absorbing substances, and to the application of such substances in combination with a special catalyst unit taking the place of a closure plug on a lead-acid storage battery, the purpose of this catalyst unit being to catalytically recombine the hydrogen and oxygen gases generated during the operation of the lead-acid storage battery to obtain water which is returned to the battery electrolyte.
2. Description of the Prior Art
It is known that considerable problems still exist in connection with the catalytic recombination of hydrogen and oxygen produced by lead-acid storage batteries, as a result of the poisoning of the active catalyst material through the gaseous compounds of antimony-hydrogen and arsenic-hydrogen, the so-called catalyst poisoning gases. These catalyst poisoning gases are produced through the reaction of hydrogen with certain alloy components of the lead used in the manufacture of lead-acid storage batteries. Primarily for reasons of improved quality, the lead alloys used for a wide variety of lead-acid storage cells frequently contain arsenic and antimony components. These alloy components combine with hydrogen to form the volatile, rather unstable, gaseous compounds of antimony hydride (SbH.sub.3) and arsenic hydride (AsH.sub.3), both being very effective as catalyst poisoning gases.
It has been variously attempted in the past to remove these so-called catalyst poisoning gases from the oxyhydrogen gas mixtures which are generated by electrical lead-acid storage batteries. For instance, on approach (U.S. Pat. No. 3,102,059) suggest that the oxyhydrogen gases, before reaching the catalyst, are made to flow over a granular bed of alumina or of a mixture of alumina and lead-dioxide on an alumina carrier. It is further known (U.S. Pat. No. 3,038,954) to arrange a bed of lead-oxide on a carrier of aluminum-oxide powder inside a battery plug in the flow path of the gases ahead of the catalytic material which recombines the hydrogen and oxygen generated by the battery. A particular shortcoming of these prior art substances is their very short span of effectiveness which can be measured in days.